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2
votes
1answer
356 views

Shader issues when creating projection using CreateOrthographicOffCenter instead of CreateOrthographic

Pre. Having these matrix transformations: var scale = Matrix.CreateScale(50f); var eye = new Vector3(0, 0, 10.0f); var view = Matrix.CreateLookAt(eye, Vector3.Zero, Vector3.Up); var projection = ...
2
votes
0answers
114 views

Unproject considering parallax depth

How can I take screen coordinates (or alternatively world coordinates on the 'primary' parallax plane) and find out what world coordinates they translate into when taking parallax depth into account? ...
2
votes
0answers
119 views

Stereo 3D: drawing 2D elements at apparent screen depth

I'm developing an application making use of DirectX11's stereoscopic features. At such I am not relying on nVidia's automatic implementation. That means I have to replicate a way to render 2d elements ...
2
votes
0answers
69 views

uniform z slices in clip-space

1) Context I'm using a regular OpenGL perspective projection matrix created with GLM (glm::perspective) and taking the inverse (glm::inverse) to transform clip-space back into view space (and world ...
1
vote
3answers
296 views

Orthographic Projection with variable FOV

We are building agame with orthographic view. The problem we face is the fact that with different resolution you can see different area of the game world. E.g. if you have higher resolution you can ...
1
vote
2answers
446 views

What is the camera direction vector for an isometric view?

What values correspond to a 3D vector for screen-normal from within an isometric game? It needs to be in game coordinates. It is a standard isometric where tiles are rotated 45 degrees and half ...
1
vote
1answer
360 views

Using gluUnProject to transform mouse position to world coordinates (LWJGL)?

I have a little LWJGL application and I have been trying to figure out how to successfully use the GLU.gluUnProject function in order to transform a given point on the screen (mouse position) to world ...
1
vote
1answer
137 views

Why are there different ways of building projection matrices?

Matrix.PerspectiveFovLH documentation page says that this method uses the following formula to build a perspective projection matrix. [w, 0, 0, 0] [0, h, 0, 0] [0, 0, zFar/(zFar - zNear), 1] [0, 0, ...
1
vote
1answer
568 views

How to do geometric projection shadows?

I have decided that since my game world is mostly flat I don't need better shadows than geometric projections - at least for now. The only problem is I don't even know how to do those properly - that ...
1
vote
1answer
55 views

Rendering order for units behind objects?

Im developing a 2D game with some fake 3D effects (parallell projection). 2D-units are able to walk in front of buildings aswell as behind them, although themselves being just 2d-objects. This leads ...
1
vote
1answer
135 views

Where is the error in my perspective projection implementation?

My question is not really a game development question, but since it's based on 3D programming, I thought it would fit best here. I've got a line made out of Point3D objects where the value of x, y, ...
1
vote
1answer
65 views

Why does everything appear backwards when using orthographic projection?

I may not be calculating my orthographic projection matrix properly. What can I do to ensure that my scene renders correctly when using orthographic projection? The rendering order appears to be ...
1
vote
1answer
319 views

Project location to perspective fake 3D view

I am trying to implement a perspective view in a 2D soccer game, such like Nintendo World Cup. In this case, the soccer pitch will look like a isosceles trapezoid, but not a rectangle in real. Here ...
1
vote
1answer
529 views

Trouble with SAT style vector projection in C#/XNA

Simply put I'm having a hard time working out how to work with XNA's Vector2 types while maintaining spatial considerations. I'm working with separating axis theorem and trying to project vectors onto ...
1
vote
1answer
1k views

Restoring projection matrix

I am learning to use FBOs and one of the things that I need to do when rendering something onto user defined FBO, I have to setup the projection, modelview and viewport for it. Once I am done ...
1
vote
2answers
83 views

How to determine the visibility of a single vertex, given a viewpoint?

I have a 3D triangle mesh, and I want to know, given a viewpoint (defined by a model, view and projection matrix), if a certain vertex is visible or not. My approach was to render the mesh using ...
1
vote
1answer
52 views

projection / view matrix: the object is bigger than it should and depth does not affect vertices [closed]

I'm currently trying to write a C 3D software rendering engine from scratch just for fun and to have an insight on what OpenGL does behind the scene and what 90's programmers had to do on DOS. I have ...
1
vote
2answers
216 views

projected textures not appear on the “back” of the mesh as well?

I want to create blood wounds on my character's bodies by using projected textures. I've watched some commentaries on games like Left 4 Dead and they say they use projected textures for the blood. But ...
1
vote
1answer
159 views

Orthogonal projection and world transform

I'm reading about projection matrix. Needs of perspective projection is obvious, but I'm not sure about orthogonal projection. Because orthogonal projection effect looks possible with only world ...
1
vote
2answers
852 views

How would I achieve diablo like 2D isometric projection?

I am in the process of coming up with an idea for a game, and I would like it to be isometric like Diablo. The problem is I have no idea how it achieves the effect of height like in the following ...
1
vote
1answer
138 views

Finding furthermost point in game world

I am attempting to find the furthermost point in my game world given the player's current location and a normalized direction vector in screen space. My current algorithm is: convert player world ...
1
vote
2answers
791 views

Rotate around a 3d Object (Software Renderer)

I have a simple 3d software renderer (SDL / C++) which can load a 3ds Model and render it (shaded) and rotate it around X Y Z - Axis. Now I would like to rotate / move around the object, meaning, the ...
1
vote
1answer
215 views

XNA draw 3d graphics in 2d game

I am programming a simple pool game in XNA. I am using Farseer for simple 2d physics but I want to use 3d graphics. My problem is I can't get the rendering to work. I have one model for the ball and ...
1
vote
0answers
1k views

Black Screen: How to set Projection/View Matrix [closed]

I have a Windows Phone 8 C#/XAML with DirectX component project. I'm rendering some particles, but each particle is a rectangle versus a square (as I've set the vertices to be positions equally offset ...
0
votes
3answers
223 views

Understanding how to go from a scene to what's actually rendered to screen in OpenGL?

I want something that explains step by step how, after setting up a simple scene I can go from that 'world' space, to what's finally rendered on my screen (ie, actually implement something). I need ...
0
votes
1answer
181 views

Simulating flight dynamics in two dimensions

I have decided that in order to improve my math skills and game programming skills I am going to work on a two-dimensional space simulator. The view of the player or camera will be from inside the ...
0
votes
2answers
100 views

What dimensions should you use for a perspective projection frustum?

What dimensions should you use for a perspective projection frustum? Initially I created a perspective matrix based on the width and height of the screen, with a calculated zNear value based on a ...
0
votes
1answer
112 views

How do you create a 2d world then view it in 3d?

I have been learning OpenGL for a while now and have a pretty good understanding so far. What I would like to know is if I create a 2D game in Orthographic Projection, is it possible to switch to a ...
0
votes
1answer
103 views

Which is the right way to build a OpenGL Projection Matrix

This time I'm trying to learn the core of matrix transformations. I dont like the idea to using a Math library and dont understand what is hapening on background, because this I'm having some ...
0
votes
3answers
157 views

Keeping raycast on the same level

I want my raycast to end at certain height(red line). But as the game is 3D and the camera rotates I can't use a fixed magnitude. What I thought was a stroke of genius, I figured I'd project the ...
0
votes
1answer
246 views

Ways to “invert Z-axis” in shader-based core-profile OpenGL?

In my hobbyist shader-based (non-FFP) GL (3.2+ core) "engine", everything in world-space and model-space is by design "left-handed" (and to stay that way), so X-axis goes from -1 ("left") to 1 ...
0
votes
3answers
267 views

Project rendering onto a polygon in the scene

I have a function that renders a simple OpenGL scene. I want to display this scene on a polygon within another scene, without the function having to know about it. For example, to display the scene on ...
0
votes
1answer
78 views

Projective texturing and falloff

I quite understand how projective texturing works. I implemented successfully a shader for that following nvidia doc. The major problem I'm facing is that with that implementation the projector ...
0
votes
1answer
40 views

Rotate final image with projection matrix

I'm trying to use space in my shadow (depth) maps in a more efficient way. If I could freely rotate the final image I get with projection matrix I could save a lot of pixels, but I don't know if it is ...
0
votes
1answer
101 views

Perspective projection computation

I'm learning OpenGL from arcsynthesis and I don't understand something about perspective projection (http://www.arcsynthesis.org/gltut/Positioning/Tut04%20Perspective%20Projection.html). When the ...
0
votes
0answers
12 views

Computing Field-of-View from window dimensions

I'm looking into computing the vertical Field-of-View (FOVy) based on the projection parameters of my camera. From this source, I've found an equation that seems to work. float ...
0
votes
0answers
56 views

Cube projection composed of smaller cubes not lining up

I am trying to make a cube projection composed of other cubes, similar to a Rubik's cube but completely static. I can get one cube to work, but when I join multiple, they don't line up. I am using ...
0
votes
0answers
60 views

Rasterizing euclidean planes

I'd like to visualize a BSP tree. To do this, I need to project an arbitrary euclidean plane onto a projection plane. I was thinking about calculating the intersections of the plane with the viewing ...
0
votes
2answers
213 views

OpenGL ES, orthopgraphics projection and viewport

I want to make some simple 2D game on iOS to familiarize myself with OpenGL ES. I started with Ray Wenderlich tutorial (How To Create A Simple 2D iPhone Game with OpenGL ES 2.0 and GLKit). That ...
0
votes
0answers
61 views

W2S, worldtoscreen from Projection Matrix and View Matrix

After a couple of days of tremendous trial and error coding, I must give up: I have a simple 3d program that I'm adding a visual layer to. Basically, I want to draw 2d icons and text over 3d objects ...
0
votes
1answer
79 views

XNA Rendering vertices that only appear within the cameras view

I'm making a game in XNA and I recall hearing that professionally made games use a technique to only render the polygons that appear within the cameras projection. I've been trying to find something ...
0
votes
1answer
271 views

Projecting world coordinates to screen coordinates issue - points disappear when origin not in view

I am trying to implement a 2d line drawing effect on a 3d mesh using Ogre. In order to do so, I perform silhouette detection on the lines of the object (this works) and then project these lines from ...
0
votes
0answers
143 views

Drawing Projected Vertices/Faces In Order

I recently created a 3d engine, and have gotten to what is (as I've found) the hardest part so far. I need to sort the objects and then draw them. I've looked at sorting algorithms, but my case is ...
0
votes
1answer
164 views

Scanline filling of polygons that share edges and vertices

In this picture (a perspective projection of an icosahedron), the scanline (red) intersects that vertex at the top. In an icosahedron each edge belongs to two triangles. From edge a, only one triangle ...
0
votes
1answer
267 views

Greiner-Hormann clipping problem

I have a set of planar polygons in 3D space defined by their vertices in counterclockwise order. Let's define the 'positive face' as being the face of the 3D polygon such as when observed, the ...
0
votes
0answers
139 views

What is the connection between an isometric angle and scale

I am trying to work out an isometric projection matrix for a custom angle. In the engine I'm using there's a projection matrix defined like so: projection.rotate(45 * (Math.PI / 180) ); scale = ...
0
votes
1answer
563 views

Easy way to project point onto triangle (or plane)

I have a mesh of triangles (navigation mesh), and a point in 3d space. This point should be "over" one of the triangles all the times. I'm trying to determine which triangle is the one the point is ...
-1
votes
1answer
180 views

Pinhole matrix problem

I made a program to represent a 3D world. I use the projection matrix we can find on wikipedia. For viewing a scene it's very nice but when I straff in the scene, everything behind the camera go on ...
-1
votes
1answer
551 views

Off center projection

I'm trying to implement the code that was freely given by a very kind developer at the following link: ...
-3
votes
1answer
55 views

projection and matrices [closed]

Many games do just fine with two projections, that can be represented by a matrix (orthographic and linear perspective). But what about projections that can't be represented by a matrix? Can you ...